A novel trinuclear iron complex was isolated from the model system of methane monoxygenases, and structurally characterized using Raman spectroscopy. The complex may serve as a precursor for the catalytically active species. Resonance Raman study of a solution sample of the complex revealed a resonance enhanced Fe-Cl stretch, which could be used to monitor the oxygen binding at this potential binding site during further mechanistic studies. In addition, hydroxo-bridged dinuclear iron and chromium complexes, synthesized as models of iron-containing proteins, have been studied by using resonance Raman spectroscopy in the hope of discovering characteristic vibrations of hydroxo-bridged dinuclear metal cores which could be used in conjunction with metallo-enzyme studies.